1. Field of the Invention
This invention relates to duct burners and more particularly, but not by way of limitation, to burners for operation in low oxygen environments such as in a turbine exhaust gas duct for raising the temperature thereof to a usable level.
2. Description of the Prior Art
Turbine exhaust gas (TEG) from gas turbines is usually considered waste gas since it has a temperature of only 600.degree. - 800.degree. Fahrenheit rendering it incapable of steam generation or the like.
Effective steam generation from air flow normally requires temperatures of 1,200.degree. - 1400.degree. Fahrenheit. The deficit temperature can easily be made up by gas burners located in the duct, but heating by gas is expensive and undesirable in the present energy crisis.
Also, it has been found that the typical TEG available has only about 16% oxygen which heretofore has been felt to be incapable of supporting combustion for burners using low grade fuel oil.
A further requirement levied by users of duct burner assemblies has been regardless of the type of fuel burners used, it is necessary to provide the capability of visually or electromagnetically monitoring the flame at each burner. This has proven difficult due to the arrangement of the burners in an array fashion and due to the fact that after intensive heat build up, the monitoring tubes either become blocked by smoke or the like or some visual or ultraviolet absorption takes place preventing adequate flame monitoring.